I. Field of the Invention
The present invention relates generally to thermal barriers and, more particularly, to a thermal barrier for a window opening.
II. Description of the Prior Art
In homes, office buildings and other types of building constructions, a great deal of heat loss occurs through the windows. This relatively large heat loss is due to the inherent nature of glass which is not a good thermal insulating material. Moreover, with the high cost of fuel for heating such buildings, the loss of heat through the windows has become very expensive.
There have, of course, been a number of previously known measures designed to reduce the heat loss through windows. For example, double and even triple pane glass has been used to reduce the heat loss through the window opening. Double and triple pane glass, however, is very expensive both to install originally in the building and particularly when replacing existing windows. The heat loss through double or triple pane glass, however, is still relatively large.
There have, furthermore, been a number of window coverings designed to provide a thermal barrier between the covering and the window and thus reduce the heat loss through the window. For example, in one thermal barrier of this type, wood is woven together into a tightly knit pattern and hung like a drape across the window opening. Such woven woods, however, are very expensive to manufacture and purchase and yet only marginally reduce the heat loss through the window.
There are still other types of previously known thermal barriers designed to reduce the heat loss through window openings. For example, U.S. Pat. No. 4,037,639 to Jones discloses a thermal barrier in which a plurality of relatively thin slats are pivotally secured together and slidably mounted on a track mounted to both sides of the window. When the barrier is in its lower position, the slats form a dead air space between the barrier and the window thus reducing the heat loss through the window. This type of thermal barrier, however, has not enjoyed wide acceptance or use for a number of different reasons. One reason is that thermal barriers of this type are very difficult to install and, once installed, are unsightly in appearance. Moreover, a relatively high heat loss due to thermal conductance through the thermal barrier still occurs.